Formulation pH and Adding L-Carnitine

Regarding your formulation and questions:

pH Adjustment

Yes, pH adjustment is likely needed for this formula to ensure optimal efficacy and stability of the active ingredients. Several of your key ingredients have specific pH requirements:

• Vitamin B3 (Niacinamide): Works best in the pH range of 4.0-7.0.
• N-Acetyl-D Glucosamine: Should be in a formula with a pH between 3-7.
• Activated Resorcinol: Has an optimum pH range of 4.5-5.5.
• Tranexamic Acid: Works well in the pH range of 3-8.

Considering the optimal range for Activated Resorcinol (4.5-5.5), which is the most sensitive to pH among your actives, aiming for a final pH between 4.5 and 5.5 is recommended. This range also falls within the suitable pH ranges for Vitamin B3, N-Acetyl-D Glucosamine, and Tranexamic Acid, as well as Light Cream Maker and Phenoxyethanol.

Measure the pH of your final mixture and adjust it if necessary using a suitable cosmetic-grade acid (like Citric Acid or Lactic Acid) or base (like Triethanolamine or Sodium Hydroxide solution) drop by drop until the desired pH is reached.

Adding L-Carnitine

Yes, you can add L-Carnitine to this formula. L-Carnitine is an amino acid known for its ability to help with skin cell turnover, reduce oiliness, provide moisture balance, and potentially help with the appearance of cellulite.

The recommended usage rate for L-Carnitine is typically 1-5%. Adding it within this range should be compatible with your existing ingredients.

As noted in the forum reply, L-Carnitine powder is alkaline (pH around 7.5-9.5 at 3% concentration). Adding it will increase the pH of your formula. This further emphasizes the need to measure and adjust the final pH to the recommended range of 4.5-5.5 after adding all ingredients, including L-Carnitine.

Adding L-Carnitine at an appropriate concentration and ensuring the final pH is within the recommended range (4.5-5.5, which is within L-Carnitine's optimal range of 3.5-8) should not cause significant negative effects and can offer additional benefits to your formulation.

Additional Stability Considerations

Based on the properties of your ingredients:

• Activated Resorcinol and Tranexamic Acid can be prone to discoloration. It is highly recommended to add Disodium EDTA at 0.2% and ActiveProtec™ OX at around 0.5-0.6% to help prevent this.
• Formulas containing Activated Resorcinol and Tranexamic Acid should be stored away from light, ideally in opaque packaging, and kept in a cool place or refrigerator for long-term stability.